OK so it's been a while since I posted.... I have a '98 Z that has a very nicely built engine in it, geting ready for turbo (yeah ready except for the cooler anyways...)
SO after the shop put the engine together, I fired it up, sounded great! Then it drops to idle around 900 RPM and it's making this bad clicking when warm, give it any RPM and the clicking goes away.
Then it started knocking (sounded like it) so I pulled the motor, brought it to the builders, they checked it out it was fine.... turns out a spark plug had broken... you could spin the plug's ceramics in the metal threads, and adjust the gap while its in the head
made a sound like knocking.
So I assembled the top end this time, timed it and all, everything perfect, put it in, and go figure the EXACT SAME CLICKING NOISE!!!! It sounds like it's comming from the timing chain area. First guess... oil pressure (the tensioner is pushed by oil pressure) but I have good pressure at idle ~35psi or so, and great at RPM >45psi. Also, it's a brand new tensioner from GM as of the first build, and was reset correctly. Any ideas helpful...
NEXT PROBLEM...
So I completely removed the megasquirt for a while to get it running right, turns out the TPS was also bad the LD9 TPS doesn't like the 2.3 HO TB there is play, some plastic and silicone fixed this today the TPS is great now no more hesitation, but it sounds like it misses at idle.
Scaned it... no missfire. BUT the spark advance is going from 0 to 40 REALLY REALLY fast at idle, give it gas and it smooths out perfectly (advances to around 28 degrees). The RPM gauge is very jumpy at idle and the car shakes a lot, made worse with the solid mounts. Ideas on what could cause the spark advance to shoot back and forth at idle would help here... one note I have is I can't seem to get the knock sensor to pick up anything even when I slam a wrench on the IDI cover... for what that's worth I think the knock sensor only pulls timing though...
thanks guys trying to get back to my cavy got side tracked with some fiero's but could use some help here
22 miles per gallon and dropping fast...
Are all your sensors matched for your ECU? Does your TPS reading jump erratically? Is it possible that your TPS is being turned back too far past its electrical limits? I'd think it's a carbon potentiometer, so turning it too far back would make it read open, or some other value it's not supposed to read.
2002 Cavalier 2200 5spd
All the sensors are original to the car, and seem to be working. The car was throwing a few codes, like TPS low voltage but I remidied that... the piece of the HO TB that goes into the TPS is flat, and the LD9 TPS has a moon shaped receptor. There used to be random values, because the trigger from the TB had some play inside the receptor of the TPS, but I fixed this and clocked it to the correct value, GM specifies a range of 0.60v at idle to a max of 5.00 volts at WOT, I set it to about 0.68 closed and at WOT it hits about 4.80 volts, the ECU reports this as 0% and 100% fine, but yes I know EXACTLY what you are talking about, the TPS was a source of non stop headache until I modified the TB to fit better (and makes the car run very bad if not right).
I'm unsure how to go about the spark timing jumping around at idle, so I may just go get a MSD unit need one anyway, but I'm still very concerned about the racket coming from the timing chain area, seriously it's kind of scary the noises it makes.
22 miles per gallon and dropping fast...
i would guess the shop founjd the broke plug and stoped looking for other problems somthing is wrong under the front cover.
my motor had a bad rod bearing and it clicked/knocked at idle and if you hit the gas it would get louder, so my guesses are either timing chain or a lifter.
Yeah it gets quiter when you hit the gas. We had the pan off and the bearings and everything looked good, and we also had the cams off, didn't see any lifter issues either.
I am assuming it is timing chain related, but has anybody else ever had this issue before? I bought a brand new timing chain, new sprockets, new guides and a new tensioner when I put it together. I was under the impression that the tensioner, after it extends with oil pressure, locks and holds that tension until you physically push it back in, maybe my brand new GM unit is defuncted. You know, as good as this build runs, it's really sickening to hear those noises at every red light/drive though...
22 miles per gallon and dropping fast...
